How do I avoid lag when dynamically loading a map chunk?

Question

I have a procedural 2d game which extends in all directions, on the surface similar to Terraria. When a player moves their camera close to the edge of the currently loaded terrain, I trigger an expand event, which loads new chunks of terrain. Each chunk is an N×N section of tiles. When I do this I get a stutter of about 1 second due to the cost of procedurally generating the new tile set.

How can I avoid that delay?

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Currently, all new chunks are loaded in the same iteration of the update loop (bad I know). My current idea is to create a queue to store the chunks and only render 1 chunk per game update.

Answer 1

Start generation early; if a player gets within 3 screen widths of the edge of the generated map start generating more chunks on that edge 1 chunk at a time.

Focus generation on the area the player is likely to go. That means follow the walkable terrain and defer sky and underground for later (when they return to the location or linger for a while).

Multi-thread the generation. You can do that easily by doing the expensive creation in the other thread and then just paste the data into the level data in the update loop.